Tiles have long been used as a finishing material for construction of buildings with a beautiful external appearance, convenience for installation, hygienic properties, convenience for cleaning, maintaining, and managing buildings, and the like, and the use of tiles has increased, recently.
Tile adhesives used to adhere tiles to walls or floors are classified into cement mortar-based adhesives, resin-based adhesives, and emulsion-based adhesives according to the type of major binding material. Among theses adhesives, cement mortar-based adhesives, which are typically referred to as tile cement mortar, have been widely used due to their economic efficiency and use convenience.
The tile cement mortar should have excellent sag resistance, long open time, and high adhesive strength. The sag resistance and adhesive strength become more important as large-sized tiles are used as finishing materials for buildings. Particularly, since construction costs are closely related to labor costs rather than material costs, open time plays an important role in construction by reducing a construction period.
In order to increase the open time, an amount of cement may be reduced, aggregates with a large particle size may be used, and/or asbestos may be used. However, when the amount of cement is reduced, adhesive strength decreases. Also, aggregates with a large particle size are not suitable for modern styles of tile installation by which a very thin layer of tile cement mortar is formed. Furthermore, the use of asbestos is prohibited due to toxicity.
In addition, a method of extending open time by adding organic and/or inorganic cement hydration retarders to a cement mortar has been widely used. According to this method, a surplus water in the cement mortar can be preserved for a long period of time by delaying the hydration of the cement, and hardening of the surface of the cement mortar, which is caused by a hydrate of the cement, can be prevented, so that open time is extended. However, although wetting capability of the cement mortar can be improved, adhesive strength thereof with respect to a substrate such as cement concrete deteriorate according to this method.